Internally cushioned tool-and-chuck lock for power hammers



Nov. 28, 1939.

J. J. ROBERTS INTERNALLYY CUSHIONED TOOL-AND-CHUCK 1200K FOR POWER HAMMERS Filed July 26, 1937 INVENTOR.

Patented Nov. 28, 1939 "UNITED STATES PATENT OFFICE,

- INTERNALLYHCUSHIONED TOOL-ANDY- CHUCK LooK FOR rowan HAMMERS John J. Roberts, Louisville, Ky. Application July 26,1937, Serial No. 155,586 1 Claim. 01. 279- 19.?)

My invention relates to improvements in the Ways and means designed for the ready installation and'efiicient holding of collaredchucks or tool-bits in their service places in powereham mers; and the objects of my invention are:

first, to. devise a lock for a collared chuck or toolbit, adapted to be clasped around either of them and adapted to hold them securely in their operative positions in the nozzle and cap of the power- 10 tool, hammer or drill, in which the lock is adapted to fit; second, to provide a helical compression spring designed to fit on over the smaller part of the cylindrical chuck-lock and adapted to slide back against the shoulder of the integral head of the lock to hold the lock in its service place in the nozzle of the power-tool; third, to produce a combination of nozzle and nozzle-cap adapted to hold said chuck, chuck-lock and cushion-spring in their relative service positions when operatively assembled therein; fourth, to devise for said nozzle and nozzle-cap a spring-pressed detent easily operative and adapted to lockthe nozzlecap in its service position on the nozzle until released by the operator; .and, bearing in mind the 28 necessary variation of speed and powerofstroke required in the average workmans power hamber to render it practicable'in general service; I have a still further object in my invention, namely, to design in my new look for said collared 30 chuck or bit an elongated head provided with a plurality of annular grooves around the inside thereof adapted to receive the collar which sur- 7 rounds the chuck o'r bit, so that in the same hammer the shank, at the option of the operator, may

88 be set in the operative zone of the reciprocating hammer-head, high forreceiving the short and necessarily light and fast strokes for calking and scaling and lower for receiving-the longer, and,

necessarily slower andheavier strokes, for stone- 40 chipping and riveting, which usually require heavier blows than the work of calking or scaling. In my present invention I have attained these objects in the practical mechanism illustrated in v the accompanying drawing which forms a part 45 of this specification, inwhich Figure I is a plan composed of two similar halves.

its contiguous and coacting parts, all shown in their relative positions, set for the'longest and heaviest strokes of the operating hammer-head. Fig. III is a plan view of the top of the head of one of the similar halves of said chuck-lock. Fig. '5 IV is an elevation of the inside of one of the halves of said chuck-and-bit lock, showing the annular grooves in the elongated head. Fig. V is an elevation of the outside'of one of the similar halves of the chuck-and-tool lock. 10

Fig. VI is a side elevation of a fragment of a collared drill-bit and one of the halves of said bit-lock shown in its normal operative position. Fig/VII is a side elevation of a collared chuck adapted to work in combination with said chuck- 5 lock, as shown in Figs., II and IX. Fig. VIII is a side elevation of the nozzle-cap adapted to serv- I ice in connection with said chuck-and-tool lock and coacting parts, as shown inFigs. IIand IX. Figure IX is a longitudinal section through the 20 middle of the nozzle, nozzle-cap and the lower part of the casing of a power hammer, including a collared bit-chuck, partly insection and partly in elevation with all its contiguous and coacting parts,all shown in their relative, operative posi- 26 'tions, set for the shortest and lightest strokes o the operating hammer-head. I Fig. X is a plan view of the top of the internal cushion-spring and Fig. XI is a side elevation of said cushion-spring. Fig. XII is a plan 30 view of the top of the steel abutment-block in- I stalled in the top of the counterbore in the nozzle; and Fig. XIII is a side elevation of said steel abutment block. 1

,In the following detail description of my invention, as illustrated in the accompanying drawing, similar characters refer to similar parts throughout the several views.

' The hammer-nozzle I may be fastened by means of screws to the lower part of the hammer casing 2 40 in which there would be ample room for any kind of mechanism adapted to operate the hammer-head,'the lower part lof which is shown in Figs. II and IX. I

The tool-and-chuck lock, or divided collet is One half 4 of the said chuck-lockis shown in Fig. II in its service position holding the chuck 5 in its operative position by means of the collar 5a imbedded in the lower annular groove taof the chuck-lock. The other similar half designated as 4, also, has been removed to enable the inner parts, the annular grooves, 4a, 4a, and other parts, to be seen in thisview. The threaded plug ly holds the detent La installed in the boring Inc. The lower end of the nozzle 1 is threaded and adapted to receive the threaded nozzle-cap 3 screwed back to the shoulder of said nozzle. Now, installed in said shoulder is a detent la adapted to be actuated by means of a compression spring lb installed behind the detent. And in the smooth face of the upper end of the nozzle-cap 3 is a small hole to into which the lower end of the spring-pressed detent, la, springs when the nozzle-cap has been screwed back on the nozzle as far as it should go. 'This detent prevents said cap from unscrewing until the operator lifts the detent back out of the retaining hole, 3b, using the notch is.

Below the head of the chuck-lock, the lower portion 4b thereof is smaller and adapted to slip-fit into the helical cushion-spring 6, as

shown in Fig. II, where the lower end of the spring 5 rests upon the-bottom of counterbore in the cap 3 and-the upper end of said spring abuts against the shoulder of the chuck-lock, 4, 4. Consequently, it may be seen that when the chuck Eis installed with its collar 5a. set in the lower annular groove 4a the end of the chuck-shank upon which the hammer-head l is adapted to strike, is set low under the hammerhead, as shown in Fig. II; and the following strokes would be heavier than they would be when the chuck-shank is set high, as shown in Fig. IX, because the operative zone of the hammer-head I is much. longer than the zone of operation shown in Fig. IX. And, assuming that the hammer-head l, is operating in both instance under the same pressure, we shall find that each of the longer strokes, as shown in Fig. II, would consume more time and a greater momentum would be developed in each stroke, when compared with the shorter hammer strokes, as shown in Fig. IX.

The cylindrical chuck 5 has a collar 5a adapted to fit into the annular grooves, 40., 4a, of the chuck-lock, 4, 4, to hold the chuck 5 in its operative position when assembled; and the hexagonal chuck-shank 5b has facets adapted to slipfit through the hexagonal mortise Hbin the abutment block H and the hexagonal mortise in the nozzle l, to prevent the rotation of the chuck. The chuck 5 has, also, been provided at its lower end with a'co'mparatively long, axial, tapered boring 5:0 having a uniform predetermined gradient and adapted to furnish an ade: quate bearing for different sizes of bits having shanks with similar tapers. And through the middle of said axial boring run two transverse drift-pin holes at right angles to each other. The lower hole 51 is drilled through the chuck 5 midway between the ends of said boring and is adapted for drifting out the tapers 8a of the shanks 8 of the large hits, as shown in Fig. II; and the upper hole 5.2 is drilled through the chuck 5 at the upper end of said axial boring and is adapted for drifting out the tapers 9a of the smaller bits 9 whose smaller tapers 9w must necessarily go deeper into said tapered boring to get an adequate chuck-bearing, as shown in Fig. IX.

The upper drift-pin hole 52 would be sufficient for drifting out tapers of all sizes of bits; but in this case, the tapers of the large bits would have to be unnecessarily long to reach the upper drift-pin hole, which is inside the nozzle-cap 3 and, consequently, the cap and spring must be removed before we can use the upper drift-pin hole. For these reasons, for large bits, it is better to have, also, the lower drift-pin hole by,

which is conveniently situated below the nozzlecap 3.

The nozzle-cap 3 is adapted with knurled rings, 3a, 3:1, for screwing on or off with the hands. And if we are using this power hammer very much as a stone-drill, we may use a stone-drill whose shank is finished like the shank of chuck 5, as illustrated in Fig. VI where the cylindrical shank it is adapted to slip-fit in the chuck-andbit lock 4, 4, and the collar Ifla is designed to fit in the annular grooves 4a, 4a, of said bit-lock; while the hexagon part lllb of the shank of the drill is made to slip-fit through the hexagonal mortise lib: in the abutment block II. By using a stone-drillwhose shank is so fabricated, we can work without the chuck 5.

In the long cylindrical head of the chuck-andb-itlock, 4, 4', the annular grooves, 4a, 4a, are made much wider than the thickness of the chuck-collar 5a,. for the purpose of allowing the chuck a certain amount of unimpeded movement forward. and backward in its service action. For when we are working with a. power hammer provided with this tool-and-chuck lock, drilling or chipping stone, we, of course, push hard on the power hammer to hold the cutting bit to its work; and this pressure causes a back thrust of the chuck 5 which forces the collar 50, up against the upper part of the groove 4a, if it be set in one of the lower grooves, as shown in Fig. II, or up against the abutment block H, if the chuck-collar 50, should be set in the upper annular groove 4a, as shown in Fig. IX. And in either case, the steel abutment block ll held in place by means of the retaining screw Ila, receives the back-thrust of the chuck 5 while'the power tool is in action.

Now, if we desire to change the chipping hammer chuck 5 shown in Fig. II, for the drill shown in Fig. VI, we use a drift-pin in the hole 5y-1to remove the bit 8 from the chucki. Then we unscrew the nozzle-cap 3 with the hand and remove from the nozzle the chuck 5, with the chuck-lock 4, 4, and the cushion-spring 6. Then We slip the spring oif the chuck lock and the two separate parts, 4, 4, of the chuck-lock unclasp from the chuck 5 and its collar 5a. And these parts, 4, 4, we clasp about the drill-shank Ill and its collar Illa; the collar fitting into the middle groove 40, for a medium stroke; and then we slip the cushion-spring 6 over. the smaller portion 4b of the bit-lock and place them up into the counterbore of nozzle l, pushing the hexagonal part lllb of the drill-shank up through the abutment block H until the head of the bitlock impinges against the abutment block II. We then screw the nozzle-cap 3 back on nozzle l until the detent la springs into the hole 3b in the rim of the cap 3, which looks the cap on securely. And the mechanism is ready for service. i

- Having described my invention and the ways and means of using it, I claim:

In a power-hammer having a reciprocating hammer-head and operating mechanism enclosed in a casing, a nozzle; an axial boring through the nozzle; a nozzle-cap mounted on said nozzle; an axial boring of predetermined size in the nozzle-cap in alignment with the axial boring in said nozzle; a counterbore in the nozzle-cap, whose walls form a coincident continuation of the walls of the counterbore in the nozzle; in combination with a tool-and-chuck lock, comprising duplicate, cylindrical halvesof a split sleeve, the upper portion thereof, serving as a head, being larger than the remaining lower portion and adapted to slip-fit in said counter-. bores, and the lower portion thereof, being adapted to slip-fit in the axial boring of the nozzlecap; a collared shank of a bit-chuck adapted to fit in said tool-and-chuck lock; a plurality of similar, annular grooves around the inside of the head of said tool-and-chuck lock, adapted to hold the collar of said shank high or low in 10 normal operation for adjusting the speed and power of stroke of said hammer by changing the zone of operation of said hammer-head; and a helical compression spring fitting in the lower end of said cap-counterbore and adapted to slip-fit over the lower portion of said tool-andchuck lock to hold the lock in its service position, said spring being adapted, also, to cushion the hammer-blows on the mechanism, when the bit-chuck-is empty.

JOHN J. ROBERTS. 

